Daily, package delivery companies collect millions of packages from thousands of locations scattered over large geographical areas and transport them to sorting facilities for processing. After processing, the packages are carried to an equally large number of destinations. To meet the rigorous schedule of today's business environment while providing accurate deliveries of packages, sorting facilities are equipped with automated transfer systems whenever possible. These transfer systems must be fast, durable, easy to repair or replace, and provide gentle but accurate handling of each package.
Initially, laborers employed at a sorting facility comprised the sorting process; that is, they had to grab, lift, carry and place packages from one sorting station to another. Such use of labor produced an exceedingly slow and inefficient system. Later systems provided conveyors that fed packages to a cluster of laborers who choose a package, picked it up, read the zip code or foreign address, then placed the package on a conveyor associated with the package's destination. That process was repeated in successively finer steps until the package was loaded onto a delivery vehicle assigned to a limited geographic area.
Presently, extensive use of manual labor has diminished as new sorting facilities are equipped with automated sorting and transfer systems that provide significantly improved package handling. For example, it is known to provide a powered feed conveyor to meter articles one-by-one onto a sorter, or to transport articles from one sorting station to another. In addition, it is known to mechanically divert articles from a feed conveyor to a multitude of output destinations. To accomplish that latter task, a device is typically positioned adjacent or under the feed conveyor and configured to knock, shove or drag the article from the conveyor. However, the reach of existing systems do not span to include multiple conveyors, often work only in conjunction with specific types of conveyors, include complex mechanisms that are relatively difficult to repair, and are unable to move as fast as many existing feed conveyors.
U.S. Pat. No. 3,071,239 (Burtness) discloses a mechanism suspended above a conveyor for knocking articles onto adjacent output destinations. Burtness includes a reversible drive motor centered over the conveyor and connected to a drive chain. Three paddles are attached to and spaced equidistant around a second chain. To remove an article from the conveyor, the second chain is driven clockwise or counterclockwise as required to knock the article to the right or left off the conveyor. Each time the second chain is rotated, the nearest paddle knocks the article off the conveyor and the remaining paddles are positioned in preparation for the following articles.
The transfer system disclosed in U.S. Pat. No. 3,246,733 (Torbet) describes an overhead bidirectional mechanism for laterally sweeping articles from a conveyor. The Torbet invention includes a housing with a retractable blade assembly including a motor and drive means. In operation, the blade rests inside the housing until directed to extend down toward the conveyor and begin a side to side sweeping movement, effectuated by swinging the blade about a horizontal axis. After sweeping the article off the conveyor, the blade retracts into the housing. When extended, the blade operates in an orbital path, downward from the housing and across the conveyor belt.
U.S. Pat. No. 3,170,572 (Harrison) describes transferring an article from one conveyor to another with a transferring station. More specifically, Harrison teaches transferring an article from one side of a specially constructed transfer platform to the other side, using cogs affixed to multiple chains mounted below the conveying surface. To transfer an article, the chains are rotated so the cogs extend upward and beyond the conveying surface to engage the article and drag it from one side of the transfer platform to the other. Once relocated, the powered rollers of the transfer platform carry the article forward to an attached conveyor section.
A programmable automated sorting system is disclosed in U.S. Pat. No. 5,620,102 (Finch). There, a roller feed conveyor transports articles toward a series of switching stations that can divert an article to the destination location adjacent the switching station. More specifically, Finch teaches laterally ejecting an article from a roller feed conveyor with a device mounted below the conveying surface.
The primary thrust of the prior art devices is to perform the single unilateral motion of removing an article from a conveyor. Such devices perform a limited function and lack versatility. For example, none can divert articles from a first conveyor across an adjacent second conveyor to an adjacent destination location. Likewise, none can direct articles in the opposite direction; that is, from a second conveyor onto a first conveyor. Finally, none can divert such physically distinct articles as large boxes and flat envelopes carried on a conventional belt conveyor.
Thus, there is a need in the art for a diverting system that spans multiple conveyor widths; operates entirely with a conventional belt conveyor; diverts articles either off of or onto a conveyor; is small, compact, uncomplicated and fast enough to keep up with modern conveyor speeds; and does not require the entire unit to be shut down for more than a few minutes in the event repairs are required.